The GAO has issued a new letter report, available here, that addresses strategies for encouraging voluntary health insurance enrollment (i.e., leaving on one side PPACA issues such as the individual mandate and insurance industry regulation). Based on interviews with analysts and stakeholders GAO reported the following strategies as likely having traction:

Notwithstanding these strategies for voluntary enrollment the mandate and regulatory elephants in the room were difficult to ignore. Of the four themes or frames cited by the interviewees, the second was "regardless of the particular approach taken to increase voluntary enrollment in the absence of an individual mandate, the availability of affordable, high-quality health care plans with a basic set of benefits, and full coverage of preventive care services is essential to encouraging voluntary enrollment in the coverage." [NPT]